This report presents the results of a study of the distribution of ground motions and structural response in the Humboldt Bay Nuclear Power Station during the Ferndale earthquake of June 7, 1975. Based on a knowledge of the motions developed at the ground surface in the free-field, computations are made using an idealized complete interaction procedure based on finite element analysis, to determine the characteristics of the motions likely to develop at the base of the Refueling Building at a depth of 85 ft below the ground surface and within the Refueling Building at a depth of 85 ft below the ground surface and within the Refueling Building at the ground surface level. The computed motions are shown to be in reasonably good agreement with those recorded at these locations in the same earthquake. In addition, the recorded motions are compared with those computed by an analysis procedure which generally meets existing requirements of the Nuclear Regulatory Commission and it is shown that the regulatory requirements lead to an entirely adequate but not excessively conservative margin of safety based on the motions recorded in this event.